Epoxy based adhesives are used in various applications in automotive, electronics, aerospace and the general industries. They are increasingly replacing conventional bonding systems such as soldering, welding, rivets, nails, screws and bolts because of the benefits they provide over these systems. Some of these benefits include bonding similar and dissimilar substrates without damaging them, better distribution of stress over wide area, better fatigue resistance and noise and vibration resistance. In certain applications in automotive and in electronics, a fast curing (or snap-cure) adhesive system is highly desirable for cycle time reduction and cost savings.
A one-component epoxy based adhesive system is preferred over a two-components system because it eliminates the mixing step, the required time to apply it, and the cooling during storage and shipping associated with the two-components system. An example of a one-component system is described in U.S. Pat. No. 4,797,455; hereby incorporated by reference.
The present invention relates to latent curing agents for epoxy resins including 100% solids epoxy compositions and water-based compositions, especially one-component 100% solids epoxy compositions. “Latent” curing agents are those curatives that in a formulated epoxy system remain inactive under normal ambient conditions but react readily with the epoxy resin at elevated temperatures. “One component” epoxy compositions are typically a blend of an epoxy resin, a curing agent and optionally an accelerator as well as additives and fillers.